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Some Take the Knife to Zimmer Surgery

The joint implant firm's heavily touted minimally invasive surgery technique draws critics.

Several years ago,



placed a huge bet on the future of artificial joint replacement.

The company began investing large sums of money in a new procedure that looked like a radical breakthrough in the world of minimally invasive surgery (MIS). By using two small incisions rather than a single giant one, with visual assistance provided by live X-ray imaging, the company had found an ideal way to lessen the scars, the hospital bills and the recovery times associated with hip-replacement surgery.

"While these results are preliminary," Zimmer CEO Ray Elliott said after 50 successful operations, "we are very optimistic that the surgical technique and Zimmer's MIS instrumentation currently developed will be the gold standard in future hip replacement."

That was three years ago. Back then, Zimmer seemed to be heralding the dawn of a bright new day in orthopedic medicine. The company was still laying out plans for its multimillion-dollar Zimmer Institute, a state-of-the-art training ground for the company's new surgery, while pledging to spend tens of millions of dollars more on its young MIS program. And Zimmer continues to say its technique is gaining traction.

One prominent physician, himself a pioneer in less radical forms of MIS and a developer of MIS instruments, has personally watched Zimmer's high-profile MIS technique attract mounting criticism at each passing meeting of the American Academy of Orthopedic Surgeons (AAOS).

"I don't think this surgery is sustainable," concludes Thomas Sculco, who serves as both surgeon-in-chief at the Hospital for Special Surgery in New York and chairman of the orthopedics department in the Weill Medical College at Cornell University. "You still find some people who are interested in it. But overall, the average orthopedic surgeon won't do it -- nor should he -- because it is fraught with potential problems."

Zimmer didn't respond to requests for comment. Its stock rose $1.22 Monday to $81.51.

Test of Time

In the beginning, at least, Zimmer's new technique looked wildly promising. Indeed, based on Zimmer's first 50 consecutive two-incision cases, the procedure seemed poised to become the first outpatient hip-replacement surgery ever.

"Seventy-five percent of these 50 patients chose to go home the day of surgery,

and 25% of the patients went home the day after," said Richard Berger, the accomplished orthopedic specialist who performed that string of surgeries. And "post-operatively, there have been no complications, no readmissions and no dislocations" associated with the procedures.

But Zimmer's star training surgeon has enjoyed far better results than some. As more surgeons have learned the technique -- and gone on to perform it on typical joint-replacement candidates -- more and more problems have surfaced.

Certainly, Zimmer's portrayal of the surgery differs sharply from recent studies presented at this year's huge annual meeting sponsored by AAOS.

"New evidence challenges claims that two-incision total hip arthroplasty leads to rapid rehabilitation, low complication rates and minimal muscle damage," Stephen B. Sherretta, executive editor of

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Orthopedics Today

, wrote in an editorial this summer. "Dissent comes in three recent studies suggesting that, rather than reaping this litany of advantages, minimally invasive two-incision total hip arthroplasty (THA) leads to the following problems: 1) substantially higher complication rates; 2) higher repeat surgery rates; and 3) more muscle and tendon damage."

Medical Industry Intelligence

, a monthly report published by the health-care information specialists at Millennium Research Group, this spring highlighted some of those same findings.

The publication noted that even a doctor whose research was subsidized by Zimmer reported high complication rates associated with MIS. Specifically, it said, Sonny Bal of the University of Missouri revealed that 25% of the patients in one MIS study suffered nerve damage and a full 10% of the total needed repeat surgery after six months' time. In a group undergoing more invasive "mini-incision" surgery, it said, those numbers dropped to 6% and 3%, respectively.

The publication said that another conference presentation further compounded concerns about the technique. In that study, the publication said, doctors set out to discover how typical hip-replacement patients -- rather than those who are younger and healthier than most -- would fare after MIS. Ultimately, it said, 14% of those "more representative" hip replacement patients encountered early complications as compared to the 3.75% who underwent traditional surgery.

Such findings have left some people wondering if Zimmer's patented technique could be fundamentally flawed.

"The results in question suggest that those attributes that make the two-incision procedure minimally invasive -- that is, small incisions, the avoidance of muscle resection and the limitations imposed on visualization as a result -- are detrimental to patient outcomes," the Millennium report stated.

Meaning of the Word

Nevertheless, patients still actively seek out those orthopedic surgeons who will use MIS to replace their joints.

David Hungerford, a professor of orthopedics at the Johns Hopkins School of Medicine, gives a simple response when that happens to him. He offers Webster's two definitions for "minimal." The first, he says, is "least necessary." The second, he adds, is "barely adequate."

"Then I ask them which definition they want to choose," Hungerford says. "And they definitely don't want 'barely adequate.'"

Thus, Hungerford performs the least amount of surgery necessary to effectively replace his patients' worn-out joints. He avoids Zimmer's two-incision technique, due to its high complication rate. But on average, he still needs just a five-inch incision -- compared to more traditional cuts of up to one foot long -- in order to perform his work.

In the past, Hungerford has co-developed orthopedic implants himself and even chaired a big MIS conference sponsored by a company now owned by Zimmer. But the doctor still stops short of marketing his own technique as MIS to patients.

"The incision is going be what it is," he says. "I need to be able to see enough to do the procedure without complications. ... And I don't want my patients getting out a tape measurer" after it's over.

To achieve his results, Hungerford utilizes a modified version of a procedure introduced in England more than two decades ago. Interestingly, however, Hungerford calls Zimmer's "new" MIS anterolateral hip replacement -- which is now attracting more interest than its breakthrough two-incision surgery -- basically the same technique that he has been using for years.

"And what I've been doing," he adds, "was around a long time before MIS ever became a buzz word."

Centerpiece of the Plan

For its part, Zimmer continues to tout MIS as a growing success.

By the first quarter of this year, the company claimed, some 50% of all hip replacements involving Zimmer products relied on MIS techniques. More recently, in its second-quarter conference call, the company again underlined the importance of MIS.

Zimmer's update in that call, described as "exhaustive" by one analyst, allowed for coverage of just two so-called hot topics by the company. The first focused on Zimmer's integration of Centerpulse, a company acquired by Zimmer in 2003 after it was left vulnerable by a massive -- and expensive -- recall of thousands of defective joints. (That deal reportedly turned Zimmer into the largest orthopedic device maker in the world.) The second hot topic proved to be MIS.

Of course, that focus would come as no surprise to some.

"Zimmer has invested heavily in pioneering MIS research and development, physician training and patient marketing, establishing itself as the undisputed leader in all things MIS," the health-care experts at Millennium noted in their April report. And "while the company's long-term prospects by no means hinge upon this technology, Zimmer currently stands to gain or lose the most from the adoption and proliferation of MIS."

During its latest call, Zimmer spoke about an entire suite of MIS offerings -- and even indicated that its less radical hip replacement is overtaking its two-incision surgery in popularity. But many physicians still associate the company's original, somewhat controversial technique with MIS in general.

Sculco -- the Hospital for Special Surgery's surgeon-in-chief -- is not among them. Moreover, he believes that even Zimmer has started to focus attention away from the two-incision approach that it once so warmly embraced. Still, he feels that the company should have begun its retreat -- as problems showed up -- one or two years earlier. And he now worries about the company's promotion of less radical techniques like those he favors himself.

"Those of us who do a lot of it believe that, with less invasive surgery, the patient does better," Sculco says. "But if they're trying to popularize this in order to sell more implants, I'm not sure that's a good thing."

Both Sculco and Hungerford began exploring less invasive surgery long before Zimmer turned MIS into the latest industry catch phrase and the centerpiece of its own future. By now, in fact, Hungerford doesn't seem to care for the term MIS at all. He sees problems with the technique for hips and knees alike. Moreover, he doubts that even less invasive surgery -- Zimmer's latest focus -- will revolutionize the field in a way that, say, laparoscopy has forever changed gallbladder operations.

After all, he points out, surgeons are still removing crucial joints and replacing them with foreign hardware.

"We're just using standard approaches with smaller incisions," he says. "A total hip replacement is not minimally invasive any way you slice it. ... It looks like a pretty big invasion to me."